Disc brake systems include a disc, often referred to as a rotor, and a caliper assembly. The disc is typically fixed to a wheel of a vehicle. The caliper assembly is disposed on or near an edge of the disc. The caliper assembly includes a pair of brake pads. The brake pads are operable to engage the disc and apply a torque to the disc in a direction opposite to its rotation. The radial position at which the sum of frictional forces created at the pad-to-disc interface is called the effective radius. Increasing the effective radius increases the torque generated by the brake. The effective radius can be increased by providing a larger diameter disc and/or by positioning the pad centroid closer to the outer radial edge of the disc.
Most brake caliper assemblies can be categorized as either Frame calipers or Fist calipers. Fist calipers typically include a support bracket, a caliper body, and a pair of connecting pins. In one known device, the support bracket is fixed to a component of the vehicle such as an axle. The brake pads are positioned on opposite sides of the disc and are typically slidably disposed on the support bracket or the caliper body. The caliper body is slidably supported by the connecting pins on the support bracket. The caliper body may include a bridge that extends axially from an inboard surface of the disc to an outboard surface of the disc. Most bridges are slightly arc-shaped to receive the radial edge of the disc. Upon actuation of the brake system, the bridge typically translates axially inboard and causes the brake pads to frictionally engage opposite sides of the disc. This often places the bridge in bending, which is an inefficient use of mass. Connecting pins generally extend over the rotor between the inboard and outboard sides of the support bracket. Minimum casting is required around the perimeter of the connecting pins. Casting clearance is also required to the wheel and rotor. Thus the rotor size is limited by these parameters as well as the connecting pin diameter.
Frame calipers generally include a support bracket, a caliper body, and a pair of connecting pins. The caliper body generally has an inboard side, an outboard side, and a caliper bridge having two sides. The Frame caliper bridge is typically thinner than a Fist caliper bridge. This allows for a larger diameter rotor within a given wheel compared to a Fist caliper. Connecting pins are generally on the inboard side of the rotor for Frame calipers due to the reduced radial packaging that a larger diameter rotor provides, which does not allow for the connecting pins to extend over the rotor. The outboard side is generally thicker than a Fist caliper outboard side. Frame calipers require more outboard packaging space which is not suitable for front brake applications where other vehicle parameters dictate wheel and rotor position.